Disclaimer

Educational content, provided as-is

Everything on SQL Practice — the tutorials, the exercises, the cheat sheet and the playground — exists to help people learn SQL. It is written and checked with care: every runnable example on this site is executed against the sample database before it is published. Even so, the material is provided “as is”, without warranty of any kind, and we cannot promise it is free of errors. If you find one, please tell us and we will fix it.

Not professional advice

Nothing here is professional, legal, financial or career advice. Decisions about production databases — schema design, migrations, performance work, anything involving real data — deserve testing in your own environment and, where the stakes are high, advice from someone who can see your actual system.

SQL dialects differ

The playground and the practice checker run SQLite, inside your browser. SQLite follows standard SQL closely but not perfectly — and MySQL, PostgreSQL, SQL Server and Oracle all differ from the standard and from each other in their own ways. Where a difference commonly bites, our tutorials say so, and the playground page lists the ones you are most likely to meet. A query that runs here may still need small changes elsewhere, and that is a property of SQL, not a defect in any one engine.

The sample data is fictional

Every company, person, email address and number in the sample database is invented. Email addresses use the example.com domain, which is reserved for documentation precisely so that no real mailbox can ever be hit. Any resemblance to a real company or person is coincidence.

Certificates are not accredited

The practice section awards completion certificates. They record that you solved the exercises — nothing more. They are not accredited, not affiliated with any institution, and not a professional qualification, and the certificate itself says so on its face.

External links

Where we link to other sites — for example, official database documentation or the licence texts of the open-source software we use — those sites are not ours, and their content and policies are their own.

Trademarks

Names of programming languages, platforms and products on this site are used only to identify what a tutorial or exercise is about. Python is a registered trademark of the Python Software Foundation. MySQL is a registered trademark of Oracle and/or its affiliates. JavaScript is a trademark of Oracle in the United States. TypeScript is a trademark of Microsoft Corporation. PostgreSQL is a trademark of the PostgreSQL Community Association of Canada. Other names belong to their respective owners. SQL Practice is independent and is not affiliated with, sponsored or endorsed by any of them. The language badges on this site are plain lettering, not the projects' logos.

Questions

Anything unclear about the above: contact@sqlpractice.co.in.